Which of the following is a wrong statement?

Options

A. `D=1//f,` where `f` is the focal length and `D` is called the refractive power of a lens
B. Power is expressed ina diopter when `f` is in metres
C. Power is expressed in diopter and does not depend on the system of unit used top measure `f`
D. `D` is positive for convergent lens and negative for divergent lens

Explanation

(c) Power is expressed in dipotre and does not depend on the system of unit to measure `F`. So,among the given options, option (c) wrong.